I use DuPont Teflon wax on the paint, and the chrome. I use Turtle Wax zip wax wah first to kill the road grime and bugs, and then wax away

 

I don't always have access to hose / car wash so I tried this,
really works wonders on paint, chrome, glass and rims.
Great for maintaining a mirror shine between wax jobs:

Prolong Waterless Wash & Shine:
http://prolong.com/appearance.aspx

Cleans medium grime and bugs off and leaves a nice shine.
Protects and rain water beads up like it was just waxed.
Truck always looks sharp and just takes a few minutes.

I believe Meguiars has a similar product also.